Adhesive bonding of a shoe sole

ABSTRACT

Embodiments of the present invention provide a method for constructing a shoe sole. Specifically, among other things, embodiments of the present invention provide a method for constructing a shoe sole including adhering an outsole to a midsole. The outsole is formed from an outsole compound. The outsole compound includes an organic compound, a porous material, and an adhesion enhancer. The organic compound has a boiling point greater than 120° C. The porous material has a specific surface area greater than two square meters per gram. The organic compound is supported on the porous material. The adhesion enhancer eliminates the need for buffing the outsole when forming the outsole from the outsole compound.

TECHNICAL FIELD

In general, the present invention relates to an adhesive bonding process and, more particularly, to adhesive bonding of a shoe sole that eliminates buffing from the process.

BACKGROUND

A shoe is an item of footwear intended to protect and comfort the human foot while doing various activities. Shoes are also used as an item of decoration. The design of shoes has varied enormously through time and from culture to culture, with appearance originally being tied to function. Additionally, fashion has often dictated many design elements, such as whether shoes have very high heels or flat ones. Contemporary footwear varies widely in style, complexity, and cost. Basic sandals may consist of only a thin sole and simple strap. High fashion shoes may be made of very expensive materials in complex construction and sell for thousands of dollars a pair. Other shoes are for very specific purposes, such as boots specially designed for mountaineering or skiing.

Known shoe soles generally have a three layered structure. They consist of an outsole, a midsole, and an inner sole. The outsole provides the shoe with an outer profile so that it meets the requirements of good grip with the respective ground. Furthermore, the outsole is typically made of a non-abrasive material to assure high wear resistance and a long lifetime of the sole. The midsole is often made of a foamed plastic (e.g., elastomers) with different densities. Based on the ability of the midsole material to deform reversibly, it absorbs or dampens mechanical impacts which are generated during the walking and running motions and which are transmitted to the body of the shoe wearer via the shoe. The damping of the mechanical impacts induced in this way can be supported by the integration of damping elements of different construction. Additionally, the midsole often serves for receiving stability or support elements which are made of lightweight and stable plastics and which support the foot during walking and running. Based on their selectively adjustable flexibility, a further function of this stability or support element is the support of the walking and running motions of the shoe wearer.

The connection of the above-referenced parts of a sole, specifically the outsole and midsole, can be realized with different methods known from the prior art. In this context, conventional methods comprise stitching, sewing, and cementing. In a sole construction of shoes, the two layers are conventionally connected by means of adhesive which has several disadvantages. Based on their constitution, presently used adhesives are often volatile and harmful to the environment because of the emission of certain dusts, gases, and industrial wastes. Additionally, the known adhesives do not form a favorable bond (e.g., between rubber and plastic sole elements) so that no durable connection is achieved and the shoe elements become detached from one another. It is therefore the problem of the present invention to provide a method for connecting together the outsole and midsole which is less expensive and less time consuming than conventional prior art methods.

SUMMARY

In general, embodiments of the present invention provide a method for constructing a shoe sole. Specifically, among other things, embodiments of the present invention provide a method for constructing a shoe sole including adhering an outsole to a midsole. The outsole is formed from an outsole compound. The outsole compound includes an organic compound, a porous material, and an adhesion enhancer. The organic compound has a boiling point greater than 120° C. The porous material has a specific surface area greater than two square meters per gram. The organic compound is supported on the porous material. The adhesion enhancer eliminates the need for buffing the outsole when forming the outsole from the outsole compound.

A first aspect of the present invention provides a method for constructing a shoe sole, comprising: providing a midsole; providing an outsole compound, wherein the outsole compound includes an organic compound, a porous material, and an adhesion enhancer, wherein the organic compound has a boiling point greater than 120° C., wherein the porous material has a specific surface area greater than two square meters per gram, and wherein the organic compound is supported on the porous material; forming an outsole from the outsole compound, wherein the adhesion enhancer eliminates the need for buffing the outsole when forming the outsole from the outsole compound; and adhering the outsole to the midsole.

A second aspect of the present invention provides a shoe sole structure, comprising: a midsole, an outsole adhered to the midsole, wherein the outsole is formed from an outsole compound, wherein the outsole compound includes an organic compound; a porous material, and an adhesion enhancer, wherein the organic compound has a boiling point greater than 120° C., wherein the porous material has a specific surface area greater than two square meters per gram, and wherein the organic compound is supported on the porous material.

A third aspect of the present invention provides a method for constructing a shoe outsole, comprising: providing an outsole compound, wherein the outsole compound includes an organic compound, a porous material, and an adhesion enhancer, wherein the organic compound has a boiling point greater than 120° C., wherein the porous material has a specific surface area greater than two square meters per gram, and wherein the organic compound is supported on the porous material; and forming an outsole from the outsole compound, wherein the adhesion enhancer eliminates the need for buffing the outsole when forming the outsole from the outsole compound.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features of this invention will be more readily understood from the following detailed description of the various aspects of the invention taken in conjunction with the accompanying drawings in which:

FIG. 1 depicts a lateral side view of a shoe according to an embodiment of the present invention;

FIG. 2 depicts a general bonding process and a Butran bonding process for bonding an outsole and a midsole according to an embodiment of the present invention;

FIG. 3A depicts a photograph of a conventional adhesive side surface;

FIG. 3B depicts a photograph of an adhesive side surface containing the adhesive enhancer according to an embodiment of the present invention;

FIG. 4A depicts a photograph of a measurement of contact angle of a conventional adhesive surface;

FIG. 4B depicts a photograph of a measurement of contact angle of an adhesive surface containing the adhesive enhancer according to an embodiment of the present invention; and

FIG. 5 depicts a diagram showing a composition and usage amount of the adhesive enhancer according to an embodiment of the present invention.

The drawings are not necessarily to scale. The drawings are merely schematic representations, not intended to portray specific parameters of the invention. The drawings are intended to depict only typical embodiments of the invention, and therefore should not be considered as limiting the scope of the invention. In the drawings, like numbering represents like elements.

DETAILED DESCRIPTION

Illustrative embodiments will now be described more fully herein with reference to the accompanying drawings, in which exemplary embodiments are shown. This disclosure may, however, be embodied in many different forms and should not be construed as limited to the exemplary embodiments set forth herein. Rather, these exemplary embodiments are provided so that this disclosure will be thorough and complete and will fully convey the scope of this disclosure to those skilled in the art. In the description, details of well-known features and techniques may be omitted to avoid unnecessarily obscuring the presented embodiments.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of this disclosure. As used herein, the singular forms “a”, “an”, and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. Furthermore, the use of the terms “a”, “an”, etc., do not denote a limitation of quantity, but rather denote the presence of at least one of the referenced items. It will be further understood that the terms “comprises” and/or “comprising”, or “includes” and/or “including”, when used in this specification, specify the presence of stated features, regions, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, regions, integers, steps, operations, elements, components, and/or groups thereof.

As indicated above, embodiments of the present invention provide a method for constructing a shoe sole. Specifically, among other things, embodiments of the present invention provide a method for constructing a shoe sole including adhering an outsole to a midsole. The outsole is formed from an outsole compound. The outsole compound includes an organic compound, a porous material, and an adhesion enhancer. The organic compound has a boiling point greater than 120° C. The porous material has a specific surface area greater than two square meters per gram. The organic compound is supported on the porous material. The adhesion enhancer eliminates the need for buffing the outsole when forming the outsole from the outsole compound.

FIG. 1 depicts a lateral side view of a shoe 5 according to one embodiment of the present invention. As shown, the shoe 5 includes outsole 10, midsole 20, and upper 30. The outsole 10 is a treaded layer secured to the bottom of the midsole 20. The outsole 10 is produced to resist wear, provide traction, and absorb shock. The midsole 20 is located between the outsole 10 and the upper 30. With running shoes, it is generally considered the most important part of the shoe. It is intended to control excessive foot motion and provide cushioning and shock absorption. Many shoes are also cushioned with gel, foam, or various manufacturer-specific technologies that are encapsulated in the midsole 20. The outsole 10, midsole 20, and upper 30 are secured together to form the base of the shoe 5. The manufacturing methods of midsole 20 and outsole 10 are well known in the art and are not described in detail.

FIG. 2 depicts a general bonding process 100 and a Butran bonding process 102 for bonding outsole 10 and midsole 20. Conventionally, to adhere the outsole 10 and midsole 20, the outsole 10 is buffed followed by the application of a primer and an adhesive to the outsole 10. More specifically, the general bonding process 100 includes a compounding step to create an outsole compound. The outsole compound is pressed to create the outsole 10. The outsole 10 is then trimmed, buffed and cleaned. A primer is applied to the outsole 10 and the outsole 10 is cemented to the midsole 20 using an adhesive. Finally, the outsole 10 and midsole 20 are pressed and attached to the upper 30.

As shown, the inclusion of the adhesion enhancer (also referred to as “Butran”) in the compounding step allows for the elimination of the buffing and cleaning steps in the Butran bonding process 102. Production of the adhesion enhancer is described in detail in U.S. Pat. No. 7,893,133.

The improved adhesive process eliminating the buffing and cleaning steps may reduce shoe manufacturing time and costs, improve outsole adhesion performance stabilization, assist in the exclusion of harmful substances produced during the buffing and/or cleaning steps that may harm the human body, and reduce potential outsole defects.

FIG. 3A depicts a photograph of a conventional adhesive side surface. FIG. 3B depicts a photograph of an adhesive side surface containing the adhesive enhancer. The surface of the adhesive side surface in FIG. 3A is smoother than the surface of the increased adhesive side surface containing the adhesion enhancer shown in FIG. 3B.

FIG. 4A depicts a photograph of a measurement of contact angle of a conventional adhesive surface. FIG. 4B depicts a photograph of a measurement of contact angle of an adhesive surface containing the adhesive enhancer.

FIG. 5 depicts a diagram showing a composition and usage amount of the adhesive enhancer. A polymer composition containing the adhesion enhancer is used to produce an outsole compound. As shown, product type A 200 includes a porous material having a specific surface area of more than 2 m²/g and an organic compound including an alcohol, phenol or another organic compound having a hydroxyl group of the alcohol or phenol and another functional group having a boiling point of more than 120° C. Product type B 202 includes a porous material having a specific surface area of more than 2 m²/g and an organic compound including an alcohol, phenol or another organic compound having a hydroxyl group of the alcohol or phenol and another functional group having a boiling point of more than 120° C. In addition, product type B 202 includes a polymer composition. In one example, the adhesion enhancer is mixed with the polymer composition to be joined to a primer having an isocyanate group so as to improve adhesion between the polymer composition and the primer. The adhesion enhancer comprises 5 to 10 parts by weight of the organic compound based on 100 parts of the porous material.

In one example, the organic compound may include at least one of alcohols, phenols, hydroxylaldehydes, hydroxyketones, dihydroxyacetones, dihydroxyphenylalanines, glucose, polyethylene glycol, polypropylene glycol, polyglycerine or poly tetra methylene glycol.

In one example, the porous material may include at least one of silica, zeolite, diatomite earth, pearlite, mulite, fly ash, pumice, scoria, organic porous materials, aerated concrete, artificially manufactured porous materials, Si-based porous materials, SiC-based porous materials, C-based porous materials, Ce-based porous materials, Nb-based porous materials, P-based porous materials, Ge-based porous materials, Al-based porous materials, Ca-based porous materials, B-based porous materials, Mg-based porous materials, Zn-based porous materials, Ti-based porous materials, Si-based composite ceramic porous materials, Ce-based composite ceramic porous materials, Nb-based composite ceramic porous materials, P-based composite ceramic porous materials, Ge-based composite ceramic porous materials, Al-based composite ceramic porous materials, Ca-based composite ceramic porous materials, B-based composite ceramic porous materials, Mg-based composite ceramic porous materials, Zn-based composite ceramic porous materials, or Ti-based composite ceramic porous materials.

The foregoing description of various aspects of the invention has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form disclosed and, obviously, many modifications and variations are possible. Such modifications and variations that may be apparent to a person skilled in the art are intended to be included within the scope of the invention as defined by the accompanying claims. 

What is claimed is:
 1. A method for constructing a shoe sole, comprising: providing a midsole; providing an outsole compound, wherein the outsole compound includes an organic compound, a porous material, and an adhesion enhancer, wherein the organic compound has a boiling point greater than 120° C., wherein the porous material has a specific surface area greater than two square meters per gram, and wherein the organic compound is supported on the porous material; forming an outsole from the outsole compound, wherein the adhesion enhancer eliminates the need for buffing the outsole when forming the outsole from the outsole compound; and adhering the outsole to the midsole.
 2. The method of claim 1, further comprising performing at least one of the following steps prior to adhering the outsole to the midsole: trimming the outsole, cutting the outsole, or applying a primer to the outsole.
 3. The method claim 1, wherein the outsole includes a polymer composition.
 4. The method of claim 3, further comprising first preparing the adhesion enhancer and mixing the adhesion enhancer with the polymer composition.
 5. The method of claim 4, wherein the adhesion enhancer is mixed with the polymer composition to be joined to a primer having an isocyanate group so as to improve adhesion between the polymer composition and the primer.
 6. The method of claim 1, wherein the adhesion enhancer comprises 5 to 10 parts by weight of the organic compound based on 100 parts of the porous material.
 7. The method of claim 1, wherein the organic compound comprises at least one of alcohols, phenols, hydroxylaldehydes, hydroxyketones, dihydroxyacetones, dihydroxyphenylalanines, glucose, polyethylene glycol, polypropylene glycol, polyglycerine, or poly tetra methylene glycol.
 8. A shoe sole structure, comprising: a midsole; and an outsole adhered to the midsole, wherein the outsole is formed from an outsole compound, wherein the outsole compound includes an organic compound, a porous material, and an adhesion enhancer, wherein the organic compound has a boiling point greater than 120° C., wherein the porous material has a specific surface area greater than two square meters per gram, and wherein the organic compound is supported on the porous material.
 9. The shoe structure of claim 1, wherein the outsole compound includes a polymer composition.
 10. The shoe structure of claim 9, wherein the adhesion enhancer is first prepared and then mixed with the polymer composition.
 11. The shoe structure of claim 10, wherein the adhesion enhancer is added to the polymer composition to be joined to a primer having an isocyanate group so as to improve adhesion between the polymer composition and the primer.
 12. The shoe structure of claim 1, wherein the adhesion enhancer comprises 5 to 10 parts by weight of the organic compound based on 100 parts of the porous material.
 13. The shoe structure of claim 1, wherein the organic compound comprises at least one of alcohols, phenols, hydroxylaldehydes, hydroxyketones, dihydroxyacetones, dihydroxyphenylalanines, glucose, polyethylene glycol, polypropylene glycol, polyglycerine or poly tetra methylene glycol.
 14. The shoe structure of claim 1, wherein the porous material includes at least one of silica, zeolite, diatomite earth, pearlite, mulite, fly ash, pumice, scoria, organic porous materials, aerated concrete, artificially manufactured porous materials, Si-based porous materials, SiC-based porous materials, C-based porous materials, Ce-based porous materials, Nb-based porous materials, P-based porous materials, Ge-based porous materials, Al-based porous materials, Ca-based porous materials, B-based porous materials, Mg-based porous materials, Zn-based porous materials, Ti-based porous materials, Si-based composite ceramic porous materials, Ce-based composite ceramic porous materials, Nb-based composite ceramic porous materials, P-based composite ceramic porous materials, Ge-based composite ceramic porous materials, Al-based composite ceramic porous materials, Ca-based composite ceramic porous materials, B-based composite ceramic porous materials, Mg-based composite ceramic porous materials, Zn-based composite ceramic porous materials, or Ti-based composite ceramic porous materials.
 15. A method for constructing a shoe outsole, comprising: providing an outsole compound, wherein the outsole compound includes an organic compound; a porous material; and an adhesion enhancer, wherein the organic compound has a boiling point greater than 120° C., wherein the porous material has a specific surface area greater than two square meters per gram, and wherein the organic compound is supported on the porous material; and forming an outsole from the outsole compound, wherein the adhesion enhancer eliminates the need for buffing the outsole when forming the outsole from the outsole compound.
 16. The method of claim 15, wherein the outsole compound includes a polymer composition.
 17. The method of claim 16, further comprising first preparing the adhesion enhancer and mixing the adhesion enhancer with the polymer composition.
 18. The method of claim 15, wherein the adhesion enhancer is mixed with the polymer composition to be joined to a primer having an isocyanate group so as to improve adhesion between the polymer composition and the primer.
 19. The method of claim 15, wherein the adhesion enhancer comprises 5 to 10 parts by weight of the organic compound based on 100 parts of the porous material.
 20. The method of claim 15, wherein the organic compound comprises at least one of alcohols, phenols, hydroxylaldehydes, hydroxyketones, dihydroxyacetones, dihydroxyphenylalanines, glucose, polyethylene glycol, polypropylene glycol, polyglycerine or poly tetra methylene glycol and the porous material includes at least one of silica, zeolite, diatomite earth, pearlite, mulite, fly ash, pumice, scoria, organic porous materials, aerated concrete, artificially manufactured porous materials, Si-based porous materials, SiC-based porous materials, C-based porous materials, Ce-based porous materials, Nb-based porous materials, P-based porous materials, Ge-based porous materials, Al-based porous materials, Ca-based porous materials, B-based porous materials, Mg-based porous materials, Zn-based porous materials, Ti-based porous materials, Si-based composite ceramic porous materials, Ce-based composite ceramic porous materials, Nb-based composite ceramic porous materials, P-based composite ceramic porous materials, Ge-based composite ceramic porous materials, Al-based composite ceramic porous materials, Ca-based composite ceramic porous materials, B-based composite ceramic porous materials, Mg-based composite ceramic porous materials, Zn-based composite ceramic porous materials, or Ti-based composite ceramic porous materials. 